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Objectives: This study aimed to evaluate possible cytotoxic effects of thermoplastic materials commonly used for occlusal splints and orthodontic appliances., Methods: Seven thermoplastics were included: three variants of the Essix sheets (C+, Plus, and Tray Rite; Dentsply Sirona), three thermoplastics (Bleach Heavy, Splint, and X-Heavy; Cavex Holland) and Invisalign (Align Technology). Cylindrical specimens (n = 24; 10 mm diameter) were incubated in cell culture medium for 24 h and 14 days. After incubation, the medium was collected, serially diluted, and dosed to primary human gingival fibroblasts in triplicate. Medium processed like the samples was used as negative control. Cell viability was evaluated by XTT and LDH assay to assess metabolic activity and membrane integrity, respectively. Next, cell cycle was assessed with flow cytometry after exposing HGFs to undiluted extracts., Results: The 24-hour and 14-day extracts did not evoke cytotoxicity after 24-hour incubation. No significant differences in cell viability (one-way ANOVA, p > 0.05 ) in the XTT and LDH assays or in cell cycle distribution between the different materials (two-way ANOVA, p > 0.05 )., Conclusion: The thermoplastics tested in the study showed no evident in-vitro cytotoxic effects. Further investigation should focus on determining which compounds are released from thermoplastic materials and assessing potential toxicity related to exposure to these compounds., Clinical Significance: Our study adds to the growing body of evidence on the biocompatibility of dental thermoplastics. This can aid clinical decision-making, as thermoplastics are expected to be safe to use in terms of cytotoxicity., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: To investigate the influence of adhesive resin application modalities on the film thickness of the adhesive resin and the effectiveness of a two-step universal adhesive (UA) bonded in self-etch (SE) bonding mode to high C-factor class-I cavity-bottom dentin., Materials and Methods: After application of the primer of G2-Bond Universal (G2B, GC), the adhesive resin was applied into standard class-I cavities (human molars) following four application modalities: (1) one layer, strongly air-blown; (2) one layer, gently air-blown; (3) two layers, each gently air-blown; (4) one layer, not air-blown. After being restored with composite, each tooth was sectioned to obtain one micro-specimen (n = 10), of which the adhesive resin film thickness was measured using optical microscopy. The micro-tensile bond strength (μTBS) was tested immediately or upon 100,000 thermocycles. Statistical analyses involved Kruskal-Wallis and Mann-Whitney U testing (p < 0.05)., Results: G2B's μTBS was significantly affected by the adhesive resin application modality and aging. Gently air-blowing the adhesive resin resulted in significantly higher immediate μTBS than strong air-blowing or no air-blowing. No significant difference in μTBS was found between single or double gently air-blown adhesive resin applications. The adhesive resin film thickness significantly varied with the application modalities., Conclusions: A too thin or too thick adhesive resin film thickness adversely affected bond strength of the two-step UA applied in SE mode and high C-factor condition., Clinical Relevance: The adhesive resin layer thickness can affect the bonding performance of two-step UAs in high C-factor cavities. Dental clinicians remain advised to avoid improper air-blowing of UAs and strictly follow the application instructions., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: Dental composites remain under scrutiny regarding their (long-term) safety. In spite of numerous studies on the release of monomers both in vitro and in vivo, only limited quantitative data exist on the in vivo leaching of degradation products from monomers and additives. The aim of this observational study was for the first time to quantitatively and qualitatively monitor the release of parent compounds and their degradation products in saliva from patients undergoing multiple restorations., Materials and Methods: Five patients in need of multiple large composite restorations (minimally 5 up to 28 restorations) due to wear (attrition, abrasion, and erosion) were included in the study, and they received adhesive restorative treatment according to the standard procedures in the university clinic for Restorative Dentistry. Saliva was collected at different time points, starting before the restoration up until 24 h after the treatment with composite restorations. Saliva extracts were analyzed by liquid chromatography-mass spectrometry., Results: Leaching of monomers and degradation products was highest within 30 min after the placement of the restorations. The highest median concentrations of monomers were recorded for UDMA, BisEMA-3, and TEGDMA; yet, besides BisEMA-3 and TEGDMA, no monomers could be detected after 24 h. Mono- and demethacrylated degradation products remained present up to 24 h and concentrations were generally higher than those of monomers. In patients with multiple restorations, degradation products were still present in the sample taken before the next operation, several weeks after the previous operation., Conclusions: Exposure to residual monomers and degradation products occurs in the first hours after restoration. Monomers are present in saliva shortly after restoration, but degradation products can be detected weeks after the restoration confirming a long-term release., Clinical Significance: Future research should focus more on the release of degradation products from monomers and additives from resin-based materials given their prolonged presence in saliva after restoration., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: An optimized oral health-related section and a video training were developed and validated for the interRAI suite of instruments. The latter is completed by professional non-dental caregivers and used in more than 40 countries to assess care needs of older adults., Methods: The optimized oral health-related section (ohr-interRAI) consists of nine items and a video training that were developed in consecutive phases. To evaluate psychometric properties, a study was conducted in 260 long-term care residents. Each resident was assessed by a dentist and by four caregivers (two who received the video training, two who did not)., Results: Mean kappa values and percent agreement between caregivers and dentist ranged between κ = 0.60 (80.2%) for dry mouth and κ = 0.13 (54.0%) for oral hygiene. The highest inter-caregiver agreement was found for dry mouth with κ = 0.63 [95% CI: 0.56-0.70] (81.6%), while for the item palate/lips/cheeks only κ = 0.27 [95% CI: 0.18-0.36] (76.7%) was achieved. Intra-caregiver agreement ranged between κ = 0.93 [95% CI: 0.79-1.00] (96.4%) for dry mouth and κ = 0.45 [95% CI: 0.06-0.84] (82.8%) for gums. Logistic regression analysis showed only small differences between caregivers who watched the video training and those who did not., Conclusions: Psychometric properties of the optimized ohr-interRAI section were improved compared to previous versions. Nevertheless, particularly the items based on inspection of the mouth require further refinement and caregiver training needs to be improved., Clinical Relevance: Valid assessment of oral health by professional caregivers is essential due to the impaired accessibility of regular dental care for care-dependent older adults.

Objectives: The aim of this study was to assess in a multi-modular manner the bone healing 1 year post root-end surgery (RES) with leukocyte- and platelet-rich fibrin (LPRF) and Bio-Gide® (BG; Geistlich Pharma North America, Inc., Princeton, USA) as an occlusive membrane., Materials and Methods: A randomized controlled clinical trial (RCT) of RES +/- LPRF and +/- BG was performed. The follow-up until 1 year post RES was performed by means of ultrasound imaging (UI), periapical radiographs (PR), and cone-beam computed tomography (CBCT)., Results: From the 50 included patients, 6 dropped-out during follow-up. For the 44 assessed patients (34 with UI and 42 with PR and CBCT), there was no evidence (p > 0.05) for an effect of LRPF, neither on UI measurements nor on CBCT assessments. On the contrary, there was an indication for a better outcome with BG. UI presented significant shorter healing time for the bony crypt surface (p = 0.014) and cortical opening (p = 0.006) for the groups with BG. The qualitative CBCT assessment for the combined scores of the apical area and cortical plane was significantly higher for BG (p = 0.01 and 0.02). The quantitative CBCT measurement for bone healing after 1 year was lower with BG (p = 0.019), as well as the percentage of non-zero values (p = 0.026), irrespective of the preoperative lesion size and type. Furthermore, UI seemed to be safer for frequent follow-up during the early postoperative stage (0-3 months), whereas CBCT gave more accurate results 1 year post RES. Amongst the assessors, the qualitative PR analysis was inconsistent for a favorable outcome 1 year post RES with LPRF (p = 0.11 and p = 0.023), but consistent for BG (p = 0.024 and p = 0.023)., Conclusions: There was no evidence for improvement of bone healing when RES was applied with LPRF in comparison with RES without LPRF. However, RES with BG gave evidence for a better outcome than RES without BG., Clinical Relevance: The addition of an occlusive membrane rather than an autologous platelet concentrate improved bone regeneration 1 year post RES significantly, irrespective of the assessment device applied. The accuracy of PR assessment is questionable.

Objectives: This study aimed to measure the microtensile bond strength (μTBS) of a new universal adhesive (UA) bonded to dentin following a quick bonding mode., Materials and Methods: The experimental UA 'SKB-100,' now commercialized as Clearfil Universal Bond Quick ('C-UBq'; Kuraray Noritake), was investigated, with Scotchbond Universal ('SBU'; 3M Oral Care) and the two-step self-etch (SE) adhesive Clearfil SE Bond 2 ('C-SE2'; Kuraray Noritake) serving as references. The adhesives were employed separately in etch&rinse (E&R) and SE modes on each tooth half following a split-tooth design and following their respective instructions for use, except for C-UBq that besides the manufacturer's instructed quick bonding mode was also applied and left untouched for 20 s prior to light curing ('C-UBq&#95;20s') and for C-SE2 that was also applied in the E&R mode. μTBS of half of the specimens was measured upon 1 week (1w), with the other half tested after 6-month (6m) storage in distilled water at 37 °C. Data were statistically analyzed using linear mixed-effects modeling and three-way ANOVA (p < 0.05). The adhesive-dentin interfaces were ultrastructurally characterized by TEM., Results: C-UBq revealed a significantly lower μTBS than C-SE2. The highest μTBS was recorded for C-UBq&#95;20s&#95;1w and C-SE2&#95;1w, both when applied in E&R mode. However, μTBS of C-UBq&#95;20s significantly decreased upon aging in both modes. C-SE2 presented the significantly highest 'aged' μTBS., Conclusion: C-UBq applied in the quick bonding mode did not underperform to the UAs applied for 20 s. Superior bonding effectiveness was achieved by C-SE2 in SE and E&R bonding modes., Clinical Relevance: Extended application time of C-UBq improved solely its immediate but not aged bonding effectiveness.

Objective: To evaluate the collection efficiency of water spray on the release of airborne composite particles during grinding of composite materials., Materials and Methods: Composite sticks (L:35 mm × W:5.4 mm × H:1.6 mm) of seven commercial dental composites were ground with a rough diamond bur (grain size 100 μm, speed 200,000 rpm). All experiments were performed in an enclosed 1-m 3 chamber with low particulate background (< 1,000 #/cm 3 ), and airborne particles were evaluated based on their electrical mobility. The number size distribution was determined by scanning mobility particle sizer (SMPS). Particles were collected by an electrostatic precipitator (ESP), and were ultramorphologically and chemically analyzed by a transmission electron microscope equipped with energy-dispersive X-ray spectroscopy (TEM-EDS)., Results: SMPS measurements confirmed that both dry and wet grinding generated high concentrations of nanoparticles particles with the highest concentration recorded during the last minute of grinding (1.80 × 10 6 - 3.29 × 10 6 #/cm 3 ), after which a gradual decline in particle concentration took place. Nevertheless, grinding with water spray resulted in a significant reduction of the number of released particles (5.6 × 10 5 - 1.37 × 10 6 #/cm 3 ). The smallest particle diameter was recorded during the last minute of grinding followed by a continuous growth for every next measurement. TEM of composite dust revealed a high concentration of particles varying in both size and shape., Conclusions: Regardless of whether the water cooling spray system was used during bur manipulation of composite materials, predominately nanoparticles were released. However, the particle concentrations were significantly decreased with water spray., Clinical Relevance: Since water spray might not be sufficient in nanoparticle collection, special care should be taken to prevent inhalation of composite dust.

Objectives: The objectives of this cross-sectional survey were to determine the prevalence of secondary caries (SC) in general population, to identify patient- and material-related factors which may affect the prevalence, and to describe some clinical characteristics of SC lesions., Materials and Methods: A total of 4036 restorations in 450 patients, who visited the university dental clinic for a regular (half) yearly checkup, were examined clinically (and radiographically) for the presence of SC. Clinical characteristics of the detected SC lesions (size, activity, and location) and the planned treatment were recorded. In addition, patients' caries-risk status was assessed according to the modified "cariogram" model., Results: In total, 146 restorations were diagnosed with SC, which gives an overall prevalence of 3.6%. Restorative material, restoration class, patient's caries risk, and smoking habits were shown to be important factors, as SC prevalence was significantly higher with composites, class II restorations, high-caries-risk patients, and smokers. Restorations' gingival margins were most frequently affected by SC. The largest number of restorations with SC (72%) was scheduled for the replacement., Conclusions: Prevalence of SC was higher with composite than with amalgam restorations, irrespective of the patient's caries-risk status. Gingival margins of class II, including MOD restorations, seem to be the place of less resistance to SC development. Management of SC seems to place a considerable burden on the health care workforce and expenditure., Clinical Relevance: Secondary caries (SC) is considered to be the main cause of dental restoration failure and one of the biggest clinical challenges related to dental composites. Nevertheless, its prevalence in daily practice is still not clear, which impedes an accurate estimation of its impact on health care costs.

Objectives: The aim of this study was to investigate the impact of the adjunct of leukocyte- and platelet-rich fibrin (LPRF) to root-end surgery (RES) on the patients' quality of life during the first week post RES., Materials and Methods: Patients in need of RES were recruited for an open randomized controlled clinical trial (RCT) with a 2 × 2 factorial design. They were randomly allocated to the test (+LPRF) and control (-LPRF) group. Each group was subsequently divided into two strata: with or without an occlusive membrane (Bio-Gide®, Geistlich Biomaterials, Switzerland; BG). After RES, the patients completed daily for 1 week a visual analog pain scale (VAS) and a 5-point Likert-type scale questionnaire concerning activity impairment, occurrence of symptoms, and medication use., Results: Fifty patients were included, equally divided between the test and control group. Only one patient in the "-LPRF+BG-group" had to take additional antibiotics due to a persistent jaw swelling. There was no evidence (p ≤ 0.05) for a difference between the test and control group in VAS, occurrence of pain symptoms, impairment of daily activities, and medication use, over the 7 days and daily during the 7 days post RES., Conclusions: There was no statistical significant evidence for improvement of patients' quality of life during the first week post RES with LPRF in comparison with RES without LPRF., Clinical Relevance: Although LPRF seems to be an inexpensive and autologous agent to reduce pain and swelling post RES, this RCT does not provide a statistical significant evidence for that.

Background: In spite of contradicting results, the high susceptibility of composites for secondary caries is still often associated with the bacterial growth-stimulating effect of released methacrylate monomers. However, most studies that showed this effect were performed with techniques having inherent limitations (spectrophotometry)., Objectives: Therefore, our objective was to determine the effect of four methacrylate monomers (2-Hydroxyethyl methacrylate (HEMA), triethylene glycol dimethacrylate (TEGDMA), ethylene glycol dimethacrylate (EGDMA), diethylene glycol dimethacrylate (DEGDMA)) on the growth of two caries-associated bacteria, Streptococcus mutans and sobrinus, and one non-cariogenic species, Streptococcus sanguinis, using TaqMan quantitative polymerase chain reaction (qPCR) to quantify bacterial DNA., Materials and Methods: Cultures were exposed to monomer solutions selected after spectrophotometric growth measurements. At baseline and predetermined time intervals, bacterial DNA was extracted and quantified with TaqMan qPCR. Biofilms grown in the presence of monomers were analyzed with scanning electron microscopy (SEM)., Results: Spectrophotometry indeed showed increased growth rates of all three strains with 5 mM TEGDMA, EGDMA, and DEGDMA and increased total biomass of S. sanguinis with 5 mM TEGDMA. However, qPCR failed to show any growth-stimulating effect of these monomers on S. mutans and S. sobrinus. In contrast, some monomers exhibited a growth-inhibiting effect on S. sanguinis. SEM revealed extracellular matter in S. sobrinus and S. sanguinis biofilms, which might be attributed to polymer formation., Conclusions: Techniques which quantify bacterial DNA are more appropriate to evaluate bacterial growth in the presence of monomers than spectrophotometry., Clinical Relevance: Even though methacrylate monomers did not affect the growth of cariogenic species, growth inhibition of S. sanguinis, a non-cariogenic antagonistic species, may lead to ecological shifts towards higher cariogenicity.

Objectives: The aim of this study was to determine and correlate the degree of conversion (DC) with Vickers hardness (VH) and translucency parameter (TP) with the depth of cure (DoC) of five bulk-fill composites., Materials and Methods: Six specimens per group, consisting of Tetric EvoCeram Bulk Fill ("TEC Bulk," Ivoclar Vivadent), SonicFill (Kerr), SDR Smart Dentin Replacement ("SDR," Dentsply), Xenius base ("Xenius," StickTech; commercialized as EverX Posterior, GC), Filtek Bulk Fill flowable ("Filtek Bulk," 3M ESPE), and Tetric EvoCeram ("TEC," control), were prepared for DC and VH: two 2-mm-thick layers, each light-cured for 10 s; one 4-mm bulk-fill, light-cured for 10 or 20 s; and one 6-mm bulk-fill, cured for 20 s. DC was measured using a Fourier-transform infrared spectrometer, VH using a Vickers hardness tester. DoC and TP were measured using an acetone-shaking test and a spectrophotometer, respectively. Data were analyzed using ANOVA and Pearson's correlation (α = 0.05)., Results: DC and VH ranged between 40-70 % and 30-80 VHN, respectively. TEC Bulk, Xenius, and SonicFill, bulk-filled as 4-mm-thick specimens, showed bottom-to-top hardness ratios above 80 % after 20 s curing. A positive linear correlation was found for bottom DC and VH. An average DC ratio of 0.9 corresponded to a bottom-to-top VH ratio of 0.8., Conclusions: Sculptable bulk-fills require 20 s, whereas 10 s curing time was sufficient for flowable bulk-fills using a high-intensity LED unit., Clinical Relevance: Clinicians should be aware that longer curing times may be required for sculptable than flowable bulk-fill composites in order to achieve optimal curing characteristics.

Objectives: This study aims to investigate the effect of modifying tricalcium silicate (TCS) cements on three key properties by adding ZrO 2 ., Materials and Methods: TCS powders were prepared by adding ZrO 2 at six different concentrations. The powders were mixed with 1 M CaCl 2 solution at a 3:1 weight ratio. Biodentine (contains 5 wt.% ZrO 2 ) served as control. To evaluate the potential effect on mechanical properties, the mini-fracture toughness (mini-FT) was measured. Regarding bioactivity, Ca release was assessed using ICP-AES. The component distribution within the cement matrix was evaluated by Feg-SEM/EPMA. Cytotoxicity was assessed using an XTT assay., Results: Adding ZrO 2 to TCS did not alter the mini-FT (p = 0.52), which remained in range of that of Biodentine (p = 0.31). Ca release from TSC cements was slightly lower than that from Biodentine at 1 day (p > 0.05). After 1 week, Ca release from TCS 30 and TCS 50 increased to a level that was significantly higher than that from Biodentine (p < 0.05). After 1 month, Ca release all decreased (p < 0.05), yet TCS 0 and TCS 50 released comparable amounts of Ca as at 1 day (p > 0.05). EPMA revealed a more even distribution of ZrO 2 within the TCS cements. Particles with an un-reacted core were surrounded by a hydration zone. The 24-, 48-, and 72-h extracts of TCS 50 were the least cytotoxic., Conclusions: ZrO 2 can be added to TCS without affecting the mini-FT; Ca release was reduced initially, to reach a prolonged release thereafter; adding ZrO 2 made TCS cements more biocompatible., Clinical Relevance: TCS 50 is a promising cement formulation to serve as a biocompatible hydraulic calcium silicate cement.

Objectives: This study aims to characterize the chemical interplay of hydraulic calcium silicate cements at dentin., Materials and Methods: Class I cavities were prepared in non-carious human third molars and filled with Biodentine (Septodont) or ProRoot MTA (Dentsply). After 1-day, 1-week, and 1-month Dulbecco's phosphate-buffered saline (DPBS) storage, the specimens were cross-sectioned perpendicular to the cement-dentin interface. The interfaces were evaluated using micro-Raman (μRaman) spectroscopy and at a higher spatial resolution using field emission gun electron probe microanalysis (Feg-SEM/EPMA)., Results: μRaman spectroscopy revealed the formation of a transition zone at the interface of both Biodentine (Septodont) and ProRoot MTA (Dentsply) with dentin, having an average thickness of, respectively, 7.5 ± 4.2 and 6.2 ± 5.4 μm, which however was not statistically different. No difference in interfacial ultrastructure and chemistry was found using μRaman spectroscopy between 1 day, 1 week, and 1 month DPBS-stored specimens. The observation of a transition zone at the cement-dentin interfaces contrasts with the EPMA data that revealed a sharper transition from cement to dentin. Again, no difference in interfacial ultrastructure and chemistry was found for different storage periods, with the exception of one 1 month DPBS-stored specimen prepared using Biodentine (Septodont). More specifically, EPMA revealed a gap of about 10-μm wide in the latter specimen that was filled up with newly formed calcium phosphate depositions., Conclusions: Up to 1 month, the interaction of hydraulic calcium silicate cements investigated did not reveal ultrastructural or chemical changes at unaffected dentin with the exception of a calcium phosphate gap-filling property., Clinical Relevance: Hydraulic calcium silicate cements were found to fill gaps by calcium phosphate deposition, however, without conducting chemical changes to the adjacent dentin.

Objectives: The objective of the study was to evaluate the effectiveness of a short fibre-reinforced composite (FRC) applied in combination with a conventional filler composite (CFC) on the fatigue resistance, fracture strength, failure mode and stress distribution, for restorations of premolars under two loading angles., Material and Methods: Thirty-two inferior premolars received extensive cavities with removal of the lingual cusp. Teeth were restored directly using 'FRC (EverX Posterior, GC) + CFC (G-aenial, GC)' or 'CFC only' and received two fatigue/fracture loadings at two different angles (0°/45°) (n = 8). Data were submitted to two-way ANOVA (α = 5 %) and Tukey test. Failure mode was analysed using SEM. Four 3D finite element (FE) models were constructed and static, linear and elastic analyses were performed. Maximum principal and von Mises stresses were evaluated., Results: All specimens survived the mechanical fatigue simulation. No statistical difference in fracture resistance was recorded between FRC + CFC and CFC only, considering both loading angles (p = 0.115). However, the 0° loading showed a statistical significant higher strength than the 45° loading (p = 0.000). Failure mode analysis revealed more repairable fractures upon 0° loading, versus more root fractures (unrepairable) upon 45° loading. FE revealed a higher amount of stress upon 45° loading, with tensile stress being imposed to the lingual cervical area., Conclusion: The fracture strength was not increased using the FRC. Loading at a 45° decreased significantly the fracture resistance., Clinical Relevance: The restoration of extensive cavities in posterior tooth is a challenge for the clinicians and the choice of the material that increases the fracture strength of tooth-restoration complex is required.

Objective: The objective of this study was to evaluate the effect of different chemical pre-treatments on the bond durability to dental zirconia., Methods: Fully sintered IPS e.max ZirCAD (Ivoclar Vivadent) blocks were subjected to tribochemical silica sandblasting (CoJet, 3M ESPE). The zirconia samples were additionally pre-treated using one of four zirconia primers/adhesives (Clearfil Ceramic Primer, Kuraray Noritake; Monobond Plus, Ivoclar Vivadent; Scotchbond Universal, 3M ESPE; Z-PRIME Plus, Bisco). Finally, two identically pre-treated zirconia blocks were bonded together using composite cement (RelyX Ultimate, 3M ESPE). The specimens were trimmed at the interface to a cylindrical hourglass and stored in distilled water (7 days, 37 °C), after which they were randomly tested as is or subjected to mechanical ageing involving cyclic tensile stress (10 N, 10 Hz, 10,000 cycles). Subsequently, the micro-tensile bond strength was determined, and SEM fractographic analysis performed., Results: Weibull analysis revealed the highest Weibull scale and shape parameters for the 'Clearfil Ceramic Primer/mechanical ageing' combination. Chemical pre-treatment of CoJet (3M ESPE) sandblasted zirconia using Clearfil Ceramic Primer (Kuraray Noritake) and Monobond Plus (Ivoclar Vivadent) revealed a significantly higher bond strength than when Scotchbond Universal (3M ESPE) and Z-PRIME Plus (Bisco) were used. After ageing, Clearfil Ceramic Primer (Kuraray Noritake) revealed the most stable bond durability., Conclusion: Combined mechanical/chemical pre-treatment, the latter with either Clearfil Ceramic Primer (Kuraray Noritake) or Monobond Plus (Ivoclar Vivadent), resulted in the most durable bond to zirconia., Clinical Relevance: As a standard procedure to durably bond zirconia to tooth tissue, the application of a combined 10-methacryloyloxydecyl dihydrogen phosphate/silane ceramic primer to zirconia is clinically highly recommended.

Objectives: The objective of this randomized controlled trial was to evaluate the clinical performance of a 2-hydroxyethyl methacrylate (HEMA)-free one-step adhesive., Materials and Methods: Two hundred sixty-seven cervical lesions in 52 patients were restored with the composite Gradia Direct (GC), bonded with either the one-step self-etch adhesive G-Bond (GC) or the three-step etch-and-rinse adhesive Optibond FL (Kerr) in a random order. The restorations were evaluated for retention, marginal integrity, marginal discoloration, and caries occurrence after 5 years. Specific statistics were used to account for the clustered data (multiple restorations per patient)., Results: The clinical success rate for G-Bond (87.4 %) was not significantly different from that of Optibond FL (90.9 %). Both adhesives showed progressive marginal deterioration, but G-Bond exhibited more small enamel defects and marginal discoloration, and unlike previous recalls, several restorations failed because of deep microleakage. Large sclerotic lesions were a significant risk factor for retention loss with G-Bond. Irrespective of the adhesive, almost all restorations with retention loss were located in the lower jaw., Conclusion: After 5 years of clinical service, restorations bonded with the HEMA-free one-step adhesive did not need repair or replacement more often than those with the three-step etch-and-rinse adhesive, and both adhesives had a high retention rate (>90 %). There were indications that G-Bond did not (self-)etch enough in some clinical situations, as G-Bond exhibited more incisal defects and marginal discolorations, and sclerotic lesions were at higher risk of retention loss., Clinical Relevance: The clinical performance of the HEMA-free one-step adhesive was clinically acceptable after 5 years.

Objectives: A dental adhesive without small and hydrophilic monomers such as 2-hydroxyethyl methacrylate (HEMA) and triethylene glycol dimethacrylate (TEGDMA) would be beneficial in order to avoid contact allergies. However, these monomers are important to increase infiltration and polymerization of the adhesive. Therefore, the purpose of this study was to evaluate the bonding effectiveness and bond durability of a more hydrophobic and biocompatible adhesive as compared to a conventional three-step etch-and-rinse adhesive., Methods: Sixteen non-carious human third molars were used to determine the micro-tensile bond strength testing (μTBS) and interfacial ultrastructure by transmission electron microscopy (TEM) of the more hydrophobic cmf adhesive system (Saremco) adhesive as compared to the control OptiBond FL (Kerr)., Results: The more hydrophobic and biocompatible three-step etch-and-rinse adhesive was able to produce a reasonable short-time bonding effectiveness. In the long term, the collagen fibrils in the hybrid layer were not effectively protected and were prone to hydrolytic degradation. As a result, long-term bonding effectiveness of this novel adhesive was very low., Conclusions: Application of a more hydrophobic adhesive without altering the application procedure considerably results in a reduced durability of the created bond, Clinical Relevance: Omitting small and hydrophilic components from the adhesive formulation may impair the durability of your composite restoration.

Objectives: The aim of this randomized controlled clinical trial was to evaluate the 4-year clinical performance of a self-adhesive resin cement, RelyX Unicem (3M ESPE), used for cementation of ceramic inlays. In addition, the influence of selectively acid-etching enamel prior to luting on the clinical performance of the restorations was assessed., Methods: Sixty-two IPS Empress 2 inlays/onlays were placed in 31 patients by two experienced clinicians. The restorations were luted with RelyX Unicem with (=experimental group: E) or without (=control group: NE) prior enamel etching with phosphoric acid. At baseline, 6 months, and 1, 2, and 4 years after placement, the restorations were assessed by two calibrated investigators using modified USPHS criteria. Ten selected samples of each group were investigated under SEM regarding morphological changes at the cement-inlay interface., Results: The recall rate at 4 years was 97%. Two restorations (1 E, 1 NE) were lost, and one (E) had to be replaced due to inlay and tooth fracture resulting in a survival rate of 95%. No significant differences between the experimental and control group were noticed regarding all criteria (McNemar, p < 0.05). An obvious deterioration in marginal integrity was observed after 4 years as only 5% (E = 7%; NE = 3%) of the restorations exhibited an excellent marginal adaptation. In 90% of the restorations small, still clinically acceptable marginal deficiencies were observed. SEM of the luting gap showed an increased wear of the RelyX Unicem cement over the 4-year period., Conclusions: The self-adhesive luting cement RelyX Unicem can be recommended for bonding of ceramic inlays/onlays. Additional selective enamel etching does not improve the clinical performance of the restorations within the 4-year period., Clinical Relevance: The self-adhesive resin composite RelyX Unicem showed acceptable clinical performance after 4 years of clinical service.

Objectives: This study aims to evaluate the influence of different surface preparation techniques on long-term bonding effectiveness to eroded dentin., Materials and Methods: Dentin specimens were eroded by pH cycling or were left untreated as control, respectively. Five different "preparation" techniques were applied: (1) cleaning with pumice, (2) air abrasion, (3) silicon polisher, (4) proxo-shape, and (5) diamond bur. The three-step etch-and-rinse adhesive OptiBond FL (O-FL; Kerr) and the mild two-step self-etch adhesive Clearfil SE Bond (C-SE; Kuraray) were evaluated. Micro-tensile bond strength was measured after water storage for 24 h and 1 year. Fracture analysis was performed by stereomicroscopy and SEM. Interfaces were characterized by TEM. Differences were statistically analyzed with a linear mixed effects model (α = 0.05)., Results: Erosion reduced bond strength in all groups, but this effect was less prominent when eroded dentin was prepared by diamond bur. Storage lowered bond strength in almost all groups significantly, but this ageing effect was more prominent for the eroded surfaces than for non-eroded controls. Whereas after 1-year control specimens revealed superior bond strength with the three-step etch-and-rinse adhesive (O-FL), the mild two-step self-etch adhesive (C-SE) revealed a better 1-year bond strength to eroded dentin. The interface at eroded dentin appeared very prone to degradation as was shown by the increased amount of adhesive failures and by the silver infiltration detected by TEM., Conclusions and Clinical Relevance: Although a minimally invasive approach should clinically always be strived for, superficial preparation (or minimal roughening) with a diamond bur is recommendable for long-term bonding to eroded dentin.

This 13-year randomized clinical trial compared the clinical effectiveness of two three-step etch-and-rinse adhesives in combination with a hybrid, stiffer composite versus a micro-filled, more flexible composite. The influence of composite stiffness on the clinical performance of one of the adhesives was assessed as well. One hundred and forty-two non-carious cervical lesions were restored with composites with contrasting stiffness. Seventy-one patients randomly received two cervical restorations placed following two out of three adhesive procedures: (1) the three-step etch-and-rinse adhesive Permaquick applied with the stiff micro-hybrid composite Amelogen Hybrid (PMQ-H, Ultradent), (2) Permaquick applied with the more flexible micro-filled Amelogen Microfill (PMQ-M, Ultradent), or (3) the "gold-standard" three-step etch-and-rinse adhesive Optibond FL applied with the micro-hybrid composite Prodigy (OFL-P, Kerr). The restorations were evaluated after 6 months, 1, 2, 3, 5, 7, and 13 years of clinical service regarding their retention, marginal integrity and discoloration, caries occurrence, preservation of tooth vitality, and post-operative sensitivity. Retention loss, severe marginal defects, and/or discoloration that needed intervention (repair or replacement) and the occurrence of caries were considered as clinical failures. The recall rate at 13 years was 77%. Bond degradation after 13 years was mainly characterized by a further increase in the presence of small but clinically acceptable marginal defects and superficial marginal discoloration. Twelve percent of the OFL-P restorations were clinically unacceptable. In the PMQ group, 22% of the PMQ-M restorations and 26% of the PMQ-H restorations needed repair or replacement. Regarding the clinical failure rate, Optibond FL scored significantly better than Permaquick (McNemar; p = 0.015). No statistically significant differences were found between the micro-filled and the hybrid composite for each of the parameters evaluated (McNemar, p > 0.05). After 13 years of clinical functioning, the clinical effectiveness of the three adhesive/composite combinations remained highly acceptable.

Unlabelled: The 5-year findings of a randomized clinical trial testing the null hypothesis that there are no differences between the clinical-wear performances of nano-, microfilled-, and conventional hybrids placed in class I and class II cavities are reported. Effects of subject-, operator-, and restoration-related variables on wear were assessed. Sixteen Tetric-C, 17 Tetric-EC, and 16 Gradia-DP restorations were placed in human molars and recalled at baseline, 6 months and at yearly intervals. The gypsum replicas at each recall were scanned (3D laser scanning), epoxy resin replicas were observed under scanning electron microscope and linear mixed models were used to study the influence of different variables on wear. The generalized vertical wear rate/month were (1.4 μm Tetric-C and Tetric-EC; 1.8 μm Gradia-DP) and volume wear rate/month were (0.017 mm(3) Tetric-EC; 0.018 mm(3) Gradia-DP, and 0.011 mm(3) Tetric-EC). Operator-cavity type interaction and surface area of restorations did significantly influence the volume wear rates (p < 0.05). The three wear patterns: fatigue cracks at heavy occlusal contact area/OCA, pitting at light OCA, and scratches/striations along the food escape pathways were evident. The three hybrids differed significantly in volume wear due to material and operator variables., Clinical Relevance: Clinically, operators and cavity type can affect restorations' wear magnitude but do not contribute to increased functional risk of fracture or harmful effect on pulp and periodontal biocompatibility.

The objective of this study was to compare the one-week bonding effectiveness of nine contemporary composite cements used to lute ceramic to dentin and to determine an appropriate processing method for pretesting failures. The microtensile bond strengths (µTBS) of different luting agents including five self-adhesive cements (Unicem, 3 M ESPE; Maxcem, Kerr; Monocem, Shofu; G-Cem, GC; and Multilink Sprint, Ivoclar-Vivadent), two self-etch cements (Panavia F2.0 and Clearfil Esthetic Cement, Kuraray), and two etch-and-rinse cements (Calibra, Dentsply, and Variolink II, Ivoclar-Vivadent) were measured using a standardized protocol. As control, a two-step self-etch adhesive combined with a restorative composite (Clearfil SE+Clearfil APX, Kuraray) were included as luting material. Depending on the processing of the pretesting failures, two groups of cements could be distinguished: (1) those with low bond strength and many pretesting failures and (2) those with relatively high bond strength and few pretesting failures. Nevertheless, the control luting procedure involving a self-etch adhesive combined with a restorative composite presented with a significantly higher µTBS. The µTBS was clearly product-dependent rather than being dependent on the actual adhesive approach. Fracture analysis indicated that failure usually occurred at the dentin-cement interface especially for the cements with low bond strength and many pretesting failures. Depending on the cement system, an adequate immediate ceramic-to-dentin bond strength can be obtained, even with self-adhesive cements that do not use a separate dental adhesive. Yet, the self-etch adhesive Clearfil SE combined with the restorative composite revealed a superior bonding performance and should therefore be preferred in clinical situations where the restoration transmits light sufficiently.

The aim of the study was to compare the clinical performance, quantitative and qualitative wear patterns of conventional hybrid (Tetric Ceram), micro-filled hybrid (Gradia Direct Posterior) and nano-hybrid (Tetric EvoCeram, TEC) posterior composite restorations in a 3-year randomised clinical trial. Sixteen Tetric Ceram, 17 TEC and 16 Gradia Direct Posterior restorations were placed in human molars and evaluated at baseline, 6, 12, 24 and 36 months of clinical service according to US Public Health Service criteria. The gypsum replicas at each recall were used for 3D laser scanning to quantify wear, and the epoxy resin replicas were observed under scanning electron microscope to study the qualitative wear patterns. After 3 years of clinical service, the three hybrid restorative materials performed clinically well in posterior cavities. Within the observation period, the nano-hybrid and micro-hybrid restorations evolved better in polishability with improved surface gloss retention than the conventional hybrid counterpart. The three hybrid composites showed enamel-like vertical wear and cavity-size dependant volume loss magnitude. Qualitatively, while the micro-filled and nano-hybrid composite restorations exhibited signs of fatigue similar to the conventional hybrid composite restorations at heavy occlusal contact area, their light occlusal contact areas showed less surface pitting after 3 years of clinical service.

Purpose: To examine whether iris pigment epithelial (IPE) cells transplanted into the subretinal space of Royal College of Surgeons (RCS) rats have the ability to rescue photoreceptors., Methods: Rat IPE (rIPE) or human IPE (hIPE) cells were transplanted subretinally in 23-day-old RCS rats. Sham injection and transplantation of ARPE-19 cells served as controls. After 12 weeks, eyes were evaluated for photoreceptor survival by morphometric analysis and electron microscopy., Results: Morphometric analysis showed photoreceptor rescue in all transplanted and sham-injected animals (number of photoreceptors/300 microm retina+/-sd: rIPE 41.67 +/- 28; hIPE 29.50 +/- 16; ARPE-19 36.12 +/- 21; sham 16.56 +/- 6) compared to age-matched, control rats (number of photoreceptors/300 microm retina+/-sd: 9.71 +/- 4). Photoreceptor rescue was prominent in IPE cell-transplanted rats and was significantly greater than sham-injected eyes (p = 0.02 for rIPE and p = 0.04 for hIPE)., Conclusion: Since IPE cells transplanted into the subretinal space have the ability to rescue photoreceptors from degeneration in the RCS rat without any harmful effects, IPE cells may represent an ideal cell to genetically modify and thus carry essential genetic information for the repair of defects in the subretinal space.

The aim of the study was to evaluate the marginal performance of direct composite additions for the correction of tooth form and position at 5 years. Composite additions were directly placed using the acid-etch technique and enamel bonding on 87 intact maxillary anterior teeth in 23 young patients (12-19 years old). The restorations were made by one operator using an ultrafine midway-filled densified restorative composite. Color slides were made at baseline and 5 years. At the 5-year recall, marginal performance was assessed by two evaluators in terms of marginal adaptation and retention, clinical microleakage, and caries recurrence. Marginal adaptation and clinical microleakage were judged on the vestibular, palatal, and proximal planes. In addition, these planes were divided into a cervical and an incisal part. No caries recurrence was noted at 5 years and no restoration was lost. Concerning marginal adaptation, only four restorations (5%) presented a severe incisal chipping and needed replacement. The restorations showed a significantly (P < 0.05) higher percentage of perfect margins incisally (37%) than cervically (15%). Canines showed the best cervical marginal adaptation (29% with perfect margins), the best results being with small unilateral restorations. Concerning clinical microleakage, 7% of the restorations were rated as clinically unacceptable due to severe marginal discoloration. Clinical microleakage was significantly more often (P < 0.05) found among smokers. In conclusion, an ultrafine midway-filled densified composite is indicated for use in stress-bearing areas in the anterior region. The type and location of the restoration are determining factors for marginal integrity.

The aim of the study was to evaluate the esthetic performance of direct composite additions in correcting tooth form and position at 5 years. Composite additions were directly placed using the acid-etch technique and enamel bonding on 87 intact maxillary anterior teeth in 23 young patients (12-19 years old). The restorations were made by one operator using an ultrafine midway-filled densified restorative composite. Color slides were made at baseline and 5 years. At the 5-year recall, esthetic performance was assessed clinically by two evaluators at chair-side in subterms of color match, translucency/opacity, surface roughness, and anatomical form. Five additional examiners scored esthetics on the 5-year slides. Of the restorations, 89% were still esthetically satisfactory after 5 years of clinical service. The remaining restorations needed replacement, mainly because of severe loss of anatomical form, to a lesser degree because of severe color mismatch. Central incisors and small unilateral restorations generally showed the best results concerning color match (68% and 74%, respectively) and surface smoothness (84% and 100%, respectively). The slide scores on color match and translucency/opacity were generally similar or somewhat better than the direct clinical scores; however, the difference were not statistically significant (P > 0.05). As far as surface roughness is concerned, the results were significantly better (P < 0.05) when recorded indirectly than by direct clinical evaluation. In conclusion, direct composite additions are a valuable and effective procedure for esthetic and conservative treatment of malformed and misaligned anterior teeth. Loss of anatomical form due to wear points to a shortcoming of the composite material used, with which a durable esthetic result cannot always be guaranteed in the long term.